1. Technical Field
Example embodiments of the present invention relate to cellular mobile communication technology, and more particularly, to a method of managing mobility of user equipment (UE) in a cellular mobile communication system that may detect a coverage hole and avoid an effect of the coverage hole on the basis of related data.
2. Related Art
A coverage hole is an area where a signal of another cell of a neighbor is locally well detected around a boundary between a cell A and a cell B that are planned to be geographically adjacent. This coverage hole may cause various problems.
FIG. 1 is a conceptual diagram illustrating a state in which a coverage hole occurs and its problem.
Referring to FIG. 1, the coverage hole is defined as an area where a signal of another cell (cell C) is well detected around a boundary between the cells A and B due to various reasons in a state in which a cell A 10 and a cell B 20 are planned to be geographically adjacent according to an operator's normal intention. The cell C may be referred to as an island cell in that local coverage is formed like an island within the coverage of other cells.
In this case, when UE 40 is handed over to an area 30 of the cell C, which is the island cell (ingress handover (HO)), and when the UE 40 is handed over from the cell C (egress handover), an HO failure probability is very high. To automatically sense the HO failure probability, the operator needs many driving tests and stored operation data.
When UEs move around the cell C, which is the island cell, an unnecessary ping-pong HO may occur, unnecessary radio resources may be consumed, and excessive signaling may adversely affect a network.
In the related art, there is a problem in that coverage-hole detection may not be systematically performed due to coverage contamination, and an error of the coverage-hole detection may be determined to be a radio link failure (RLF) and processed through an RLF recovery process or merely recognized as a failure.